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    <title>Document</title>
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  <body>
    <script>
      // 柯里化
      //请实现以下效果
      function add(a, b, c) {
        return a + b + c
      }
      // console.log(add.length);

      const res = add(1, 2, 3) //6

      //要求声明一个curry函数，函数add经过curry函数的处理后，每次调用只能接收一个参数
      const curry = fn => {
        let num = fn.length
        let index = 1
        let fn1 = function (...arr) {
          if (arr.length !== index) {
            throw new Error('只能输入一个数字')
          }
          index++
          if (num === arr.length) {
            return fn(...arr)
          } else {
            return fn1.bind(null, ...arr)
          }
        }
        return fn1
      }

      let addCurry = curry(add)

      // console.log(addCurry)
      // console.log(addCurry);
      const res2 = addCurry(1)(2)(3) //6
      console.log(res2)
      // console.log(res2)
    </script>
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